Vitamins and Deficiencies Quiz
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Questions and Answers

What causes a deficiency of pyridoxine (B6) despite its rarity?

  • Chronic alcohol consumption
  • Isoniazid medication (correct)
  • High intake of raw egg whites
  • Excessive consumption of fruits

    • What is a notable consequence of excessive pyridoxine (B6) intake?

  • Visual disturbances
  • Improvement in cognitive function
  • Increased energy levels
  • Peripheral sensory neuropathy (correct)

    • Which of the following substances can interfere with biotin absorption?

  • Fruits and vegetables
  • Raw egg whites (correct)
  • Dairy products
  • Whole grains

    • Biotin is essential for which type of biochemical reactions?

    <p>Carboxylation reactions</p> Signup and view all the answers

    Which of these is a symptom of biotin deficiency?

    <p>Dermatitis</p> Signup and view all the answers

    What is the primary role of thiamine (B1) in the body?

    <p>Acts as a coenzyme in glucose metabolism</p> Signup and view all the answers

    Which characteristic differentiates vitamins from macronutrients?

    <p>Vitamins are individual units</p> Signup and view all the answers

    Which of the following conditions is associated with thiamine deficiency?

    <p>Korsakoff's syndrome</p> Signup and view all the answers

    How are fat-soluble vitamins absorbed into the bloodstream?

    <p>Directly into lymph before entering blood</p> Signup and view all the answers

    What is a common result of thiamine deficiency that affects the nervous system?

    <p>Wasting and partial paralysis</p> Signup and view all the answers

    Which of the following statements is true regarding water-soluble vitamins?

    <p>They must be supplemented regularly due to rare storage</p> Signup and view all the answers

    Which of the following symptoms is part of Wernicke's encephalopathy?

    <p>Ocular disturbances</p> Signup and view all the answers

    What type of reactions is riboflavin (B2) primarily involved in?

    <p>Reduction/oxidation (redox) reactions</p> Signup and view all the answers

    What is a primary source of B vitamins?

    <p>Meat and seafood</p> Signup and view all the answers

    What is a severe symptom of untreated Wernicke's encephalopathy?

    <p>Coma and death</p> Signup and view all the answers

    What is a risk associated with unnecessary supplementation of fat-soluble vitamins?

    <p>Higher likelihood of toxicity</p> Signup and view all the answers

    Thiamine pyrophosphate (TPP) is necessary for which of the following reactions?

    <p>Decarboxylation reactions</p> Signup and view all the answers

    Which vitamin is known as Cobalamin?

    <p>Vitamin B12</p> Signup and view all the answers

    What is a common way B vitamins are added back to processed foods?

    <p>Through the use of enriched flour</p> Signup and view all the answers

    Which symptoms are indicative of Korsakoff's syndrome?

    <p>Amnesia and confabulation</p> Signup and view all the answers

    What role do vitamins primarily play in biological systems?

    <p>They function as coenzymes to facilitate enzyme activity</p> Signup and view all the answers

    What is the primary role of the active form of vitamin D?

    <p>Maintaining adequate plasma calcium levels</p> Signup and view all the answers

    Which organ is involved in increasing calcium absorption due to vitamin D?

    <p>Intestine</p> Signup and view all the answers

    What can vitamin D deficiency trigger in terms of bone health?

    <p>Secondary hyperparathyroidism</p> Signup and view all the answers

    What is the recommended daily intake range for vitamin D?

    <p>200-600 IU</p> Signup and view all the answers

    Which condition is specifically caused by vitamin D deficiency in children?

    <p>Rickets</p> Signup and view all the answers

    What can be a consequence of vitamin D toxicity?

    <p>Increased thirst</p> Signup and view all the answers

    What role does Vitamin A play in the cornea?

    <p>It maintains healthy, transparent surfaces for clear vision.</p> Signup and view all the answers

    Which population factor can contribute to vitamin D deficiency?

    <p>Dark skin</p> Signup and view all the answers

    What is a consequence of Vitamin A deficiency?

    <p>Night blindness and xerophthalmia.</p> Signup and view all the answers

    At what dosage of vitamin D do serious toxicity symptoms become likely?

    <p>100,000 IU/day for weeks</p> Signup and view all the answers

    What is the function of retinoic acid in epithelial tissues?

    <p>It supports normal differentiation of epithelial tissues.</p> Signup and view all the answers

    Which form of Vitamin A is important for transporting Vitamin A in the blood?

    <p>Retinol</p> Signup and view all the answers

    Which of the following is NOT a source of Vitamin A?

    <p>Fruit juices</p> Signup and view all the answers

    What is one of the clinical uses of retinoic acid?

    <p>Dermatological treatments.</p> Signup and view all the answers

    What condition can arise due to a lack of retinol during fetal development?

    <p>Abnormal fetal development.</p> Signup and view all the answers

    Which statement about rhodopsin is correct?

    <p>It is involved in the retinal cycle.</p> Signup and view all the answers

    What is the primary function of vitamin E in the body?

    <p>Prevent oxidation of LDL cholesterol</p> Signup and view all the answers

    Which form of vitamin E has the highest activity in the body?

    <p>Alpha-tocopherol</p> Signup and view all the answers

    What is a common result of vitamin E deficiency in premature infants?

    <p>Hemolytic anemia</p> Signup and view all the answers

    What dietary sources are known to be high in vitamin E?

    <p>Vegetable oils and nuts</p> Signup and view all the answers

    Which vitamin is essential for post-translational modification of certain coagulation factors?

    <p>Vitamin K</p> Signup and view all the answers

    How does vitamin K assist in the coagulation process?

    <p>As a coenzyme of gamma glutamyl carboxylase</p> Signup and view all the answers

    What has been observed about high doses of vitamin E supplementation?

    <p>It may increase the risk of stroke</p> Signup and view all the answers

    Which of the following is a characteristic of vitamin K?

    <p>It has multiple forms including synthetic variants</p> Signup and view all the answers

    Study Notes

    Lecture 9: Vitamins

    • Vitamins are chemically unrelated, essential organic compounds.
    • They cannot be synthesized in adequate amounts by the human body.
    • Vitamins differ from macronutrients (proteins, carbohydrates, and fats) in structure and function.
    • Vitamins are typically present in small quantities in food.
    • Water-soluble vitamins (B vitamins and vitamin C) are absorbed directly into the bloodstream.
    • Fat-soluble vitamins (vitamins A, E, D, and K) enter the lymphatic system and then the bloodstream.
    • Fat-soluble vitamins are often stored in the body, while water-soluble vitamins are rarely stored. Excess intake of fat-soluble vitamins can lead to toxicity.
    • Vitamins function as coenzymes, assisting enzymes in various metabolic processes.
    • A variety of food sources contain B vitamins, including meat, seafood, legumes, whole grains, potatoes, bananas, chili peppers, tempeh, nutritional yeast, and brewer's yeast.
    • Thiamine (B1) is part of the coenzyme thiamine pyrophosphate (TPP), playing a major role in glucose metabolism. It facilitates decarboxylation and transferase reactions and is involved in the synthesis of acetylcholine.
    • Thiamine deficiency (beriberi) is associated with severe weakness and can affect the nervous system, heart, and skeletal muscles. Chronic alcoholics and malnourished people are at risk.
    • Riboflavin (B2) is part of the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), essential for redox reactions in energy metabolism.
    • Riboflavin deficiency is not usually severe but may be associated with angular cheilitis, glossitis, photophobia, itching, and burning eyes.
    • Niacin (B3) exists as nicotinic acid and nicotinamide. It's crucial in redox reactions as part of NAD+ and NADP+. Niacin deficiency (pellagra) leads to symptoms like diarrhea, dermatitis, dementia, and death.
    • Pantothenic acid (B5) is part of Coenzyme A (CoA), helping with acyl group transfers in various metabolic pathways. Deficiency and toxicity are rare.
    • Pyridoxine (B6) exists as pyridoxal, pyridoxine, and pyridoxamine, which are converted to the active coenzyme pyridoxal phosphate. It's involved in amino acid metabolism, glycogen metabolism, and heme and lipid synthesis. Toxicity is rare but can be seen in high-dose use or consumption of isoniazid.
    • Biotin (B7) participates in carboxylation reactions, playing crucial roles in gluconeogenesis and fatty acid synthesis. Deficiency is rare.
    • Folate (B9) is essential for one-carbon compound transfers, DNA synthesis, and cell division. Deficiency leads to megaloblastic anemia, neural tube defects, and impacts pregnancy.
    • Vitamin B12 is essential for the remethylation of homocysteine to methionine, degradation of certain amino acids and odd-carbon fatty acids. Deficiency may accumulate unusual fatty acids within cell membranes. Vitamin B12 is synthesized by microorganisms and is only found in animal products.
    • Vitamin C (ascorbic acid) is crucial for collagen formation and other reactions like tryptophan to serotonin and tyrosine to norepinephrine conversion. Acts as an antioxidant. Severe deficiency can lead to scurvy.
    • Vitamin A is found in a variety of foods (liver, kidney, cream, egg yolk, yellow, orange, and dark green vegetables, and fruits). Deficiency can lead to night blindness and xerophthalmia (cornea and conjunctiva dryness).
    • Vitamin A has various forms including retinol, retinal (aldehyde), and retinoic acid, useful in vision, reproduction, growth, and maintenance of epithelial tissues. Retinoic acid is useful in specific dermatological conditions and the treatment for promyelocytic leukemia. Excess vitamin A consumption can be toxic.
    • Vitamin D is produced in the skin through sun exposure and does not require external intake from foods. Activated via two hydroxylation reactions, in the liver and in the kidneys, to be absorbed into the body effectively. Vitamin D is critical for maintaining adequate plasma calcium levels, and has additional roles in supporting calcium absorption in the intestines and kidneys, and in bone metabolism.
    • Vitamin D deficiency can cause rickets in children (deformed, soft, flexible bones) and osteomalacia in adults (deformed and brittle bones).
    • Vitamin E is an antioxidant that protects against free radical damage, especially in plasma membranes. Vitamin E protects against inflammation, atherosclerosis, hemolytic anemia. It is found in high quantities in vegetable oils (soybean, corn, safflower, cottonseed)
    • Vitamin K is important for post-translational modification of certain coagulation factors (II, VII, IX, X) and osteocalcin, and for proper blood clotting. It's found in cabbage, kale, spinach, egg yolk, and liver. Deficiency is rare except in newborns.
    • Deficiency and toxicity of these vitamins can cause a broad range of symptoms and health problems.

    Learning Objectives

    • Describe vitamins in general
    • Know water-soluble vitamins, their cellular roles, deficiency disorders and symptoms.
    • Know fat-soluble vitamins, their absorption, storage, forms, functions, and related toxicity.
    • Describe the function of vitamins as coenzymes in promoting enzyme activity

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    Lecture 9 Vitamins Jan 2023 PDF

    Description

    Test your knowledge on vitamins, particularly B vitamins, their deficiencies, and impacts on health. This quiz covers sources, symptoms, and biochemical roles of essential vitamins such as pyridoxine, biotin, and thiamine. Assess your understanding of water-soluble and fat-soluble vitamins.

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